The side covers of the filter are made from rigid plastic with integrated water outlet slopes on both the up and down stream sides. Connection slots for the insertion of the pre-filter frame HFA-# are also included. These features, in combination with the reinforced profiles, provide maximum space for the filter media pack and obtain a high mechanical strength. The fibreglass media pleated in ‘mini-pleat shape’ can be reinforced with an additional plastic rib that is cast with polyurethane sealant in V-shape technology directly into the side cover. This design provides a very high burst pressure in correlation with maximum dust holding capacity, low pressure drop, and safe removal of condensate water. The filters are supplied with a flat flange and endless gasket creating a secure seal between the filter and each standard pre-filter holding frame.